This invention relates generally to single or multi-pole circuit breakers, and more particularly to stored energy circuit breakers having manual and motor operated drive means.
The basic functions of circuit breakers are to provide electrical system protection and coordination whenever abnormalities occur on any part of the system. The operating voltage, continuous current, frequency, short circuit interrupting capability, and time-current coordination needed are some of the factors which must be considered when designing a breaker. Government and industry are placing increasing demands upon the electrical industry for interrupters with improved performance in a smaller package and with numerous new and novel features.
Stored energy mechanisms for use in circuit breakers of the single pole or multi-pole type have been known in the art. A particular construction of such mechanisms is primarily dependent upon the parameters such as rating of the breaker. Needless to say, many stored energy circuit breakers having closing springs cannot be charged while the circuit breaker is in operation. For that reason, some circuit breakers have the disadvantage of not always being ready to close in a moment's notice. These circuit breakers do not have, for example, an open-close-open feature which users of the equipment find desirable.
Another problem present in some prior art circuit breakers is that associated with matching the spring torque curve to the breaker loading. These prior art breakers utilize charging and discharging strokes which are each 180.degree.. The resulting spring torque curve is predetermined, and usually cannot be matched with the breaker loading. Such a predetermined curve mandates that the elements associated with the breaker be matched for this peak torque rather than be matched with the breaker load curve.
A desirable characteristic in these circuit breakers is for the current carrying parts to be electrically isolated from the operating mechanism of the breaker. By so isolating the current carrying parts, temporary emergency repairs to the operating mechanism may be undertaken.
Another desirable characteristic in these circuit breakers is to provide for both manual and motor driven operation of the operating mechanism. This dual capability should be provided so that critical alignment of the connection of the motor to the operating mechanism is not necessary, and this connection of the motor to the operating mechanism should also be capable of being easily installed in the field in the unlikely event of a motor failure.